The crankcase of an engine must be vented in order to prevent an undue build-up of pressure and explosive vapors which have escaped past the piston rings into the crankcase while the engine is running. The fumes or vapors found in an engine crankcase include a portion of the engine lubricating oil either as a vapor or in a droplet form and unburned carbon particles coated with oil, the constituents being suspended in the fumes. Separators are commonly used to recover the oil droplets from the fumes. The remaining fumes are of an oily consistency, dark in color and have an odor which is offensive to smell.
An example of a crankcase ventilation system is disclosed in U.S. Pat. No. 2,916,020 issued to Adelbert E. Kolbe on Dec. 12, 1958. In such system, the crankcase fumes are separated into separated oil and gaseous fumes. The oil flows through openings in the block back into the pan. The remaining fumes are exhausted to the atmosphere through a vent tube.
Another example of a crankcase ventilation system directs the remainder of the crankcase fumes from the separator to the fan portion of an engine so that the fumes are dissipated in the cooling air. A drawback to such a system is that the oily fumes enter the radiator and cling to the fins. Dust particles flowing through the radiator are absorbed in the oil and the radiator becomes clogged resulting in overheating of the engine.
Another example of a crankcase ventilation system is disclosed in U.S. Pat. No. 3,241,535 issued to William R. Drysdale on Mar. 22, 1966. In such system, the crankcase fumes are drawn by intake manifold pressure from the crankcase through a tube to the intake manifold which delivers them to the combustion chamber.
Another example of a crankcase ventilation system is disclosed in U.S. Pat. No. 3,630,182 issued to Lewis M. D. Granger on Dec. 28, 1971. In this system, the crankcase fumes are drawn from the crankcase of the engine and mixed with fresh air. The mixture is fed through a heat exchanger to heat the gases and into an oil bath air cleaner air intake of the carburetor. A portion of the fumes and air are also fed to an exhaust-gas-pollution-burning device.
The oily carbon particles when recirculated through the intake manifold of an engine will tend to cling to the walls and cake thereupon. As heat from the engine combustion cycle is added to the oily carbon particles, the tendency for caking increases. Furthermore, caking near the valves will cause the valve seat to overheat and crack resulting in oil leakage past the seat and into the intake passage. Such oil compounds the caking problem by combining with the caking mixture forming a build-up which becomes excessive to the point where the engine malfunctions. If, however, the oily carbon particles and fumes are not recirculated through a combustion or burning process, the dark oily fumes emitted from the engine will pollute the atmosphere.
The present invention is directed to overcoming one or more of the problems as set forth above.